Alkenyl-functional polydiorganosiloxane compositions and methods for use thereof in forming wood plastic composites

ABSTRACT

An alkenyl-functional polydiorganosiloxane is useful in a composition and a method for preparing a wood plastic composite article. The wood plastic composite article is useful as a building material. The polydiorganosiloxane may be added in liquid form to a composition, or may form part of a solid carrier component, used to make the wood plastic composite article.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a U.S. national stage filing under 35 U.S.C. § 371of PCT Application No. PCT/US2020/036890 filed on 10 Jun. 2020,currently pending, which claims the benefit of U.S. Provisional PatentApplication No. 62/883,682 filed 7 Aug. 2019 under 35 U.S.C. § 119 (e).PCT Application No. PCT/US2020/036890 and U.S. Provisional PatentApplication No. 62/883,682 are hereby incorporated by reference.

TECHNICAL FIELD

A polydiorganosiloxane is useful in a wood plastic composite (WPC)composition and method for preparing WPC articles. Thepolydiorganosiloxane may be delivered in liquid or solid form.

BACKGROUND

Conventional processes for producing WPC articles generally require aprocess aid (which can be internal or external) to facilitate formingand ensure quality (e.g., smoothness of surface and edges) of the WPCarticles. Conventional, low cost, organic process aids generally sufferfrom the drawback of requiring high loading to achieve faster productionspeeds, thereby impacting cost and/or performance properties. Inaddition, many conventional process aids may negatively affect physicalproperties and reduce mechanical properties (such as impact resistance,flexural strength, and flexural modulus) of the WPC articles, especiallyat elevated use temperatures. Conventional process aids may also migratefrom the WPC articles, thus negatively impacting one or more propertiesof the WPC articles over time, such as physical properties, appearance,feel, ability to overmold, ability to co-extrude, ability to adhere tothe surface, ability to print the surface or ability to paint thesurface of the WPC articles. In addition, some of the organic processaids volatilize at higher application temperatures, which can lead toformation or bubbles and cracks in the WPC articles, which cancompromise long term performance of these articles.

SUMMARY

A composition comprises: (a) a lignocellulosic-based filler; (b) anethylene-based polymer; and (c) a polydiorganosiloxane having at leastone silicon bonded alkenyl group per molecule and a viscosity of 2,000mPa·s to 60,000 mPa·s measured at 25° C. at 0.1 to 50 RPM on aBrookfield DV-III cone & plate viscometer with #CP-52 spindle. A methodfor preparing a wood plastic composite article from the composition isalso disclosed.

A solid carrier component comprises:

(i) the polydiorganosiloxane described above as starting material (c);and

(ii) a polymer component selected from the group consisting of:

-   -   an ethylene-based polymer,    -   a maleated ethylene-based polymer, and    -   a combination of both the ethylene-based polymer and the        maleated ethylene-based polymer. The solid carrier component may        be useful for delivering the polydiorganosiloxane to the        composition.

DETAILED DESCRIPTION

The composition described above is useful for preparing a wood plasticcomposite article. The composition may comprise:

15 weight % to 70 weight % of (a) a lignocellulosic-based filler;

29.5 weight % to 84.5 weight % of (b) an ethylene-based polymer;

0.5 weight % to 6 weight % of (c) a polydiorganosiloxane of unitformula:(R₂R′SiO_(1/2))_(a)(R₃SiO_(1/2))_(b)(R₂SiO_(2/2))_(c)(RR′SiO_(2/2))_(d),where each R is an independently selected monovalent hydrocarbon groupof 1 to 18 carbon atoms that is free of aliphatic unsaturation, each R′is an independently selected alkenyl group of 2 to 18 carbon atoms,subscript a is 0 to 2, subscript b is 0 to 2, a quantity (a+b)=2,subscript c≥0, subscript d≥0, a quantity (a+d)≥1, and a quantity(a+b+c+d) is sufficient to give the polydiorganosiloxane a viscosity of2,000 mPa·s to 60,000 mPa·s at 25° C. measured at 0.1 to 50 RPM on aBrookfield DV-III cone & plate viscometer with #CP-52 spindle; and

0 to 4 weight % of (d) a maleated ethylene-based polymer;

each based on combined weights of starting materials (a), (b), (c), and(d) in said composition.

(a) Lignocellulosic-Based Filler

The composition described above comprises starting material (a) alignocellulosic-based filler. The lignocellulosic-based fillercomprises, alternatively consists essentially of, alternatively consistsof, a lignocellulosic material. Typically, the lignocellulosic-basedfiller consists of the lignocellulosic material. Thelignocellulosic-based filler, as well as the lignocellulosic material,may comprise any matter derived from any plant source. When thelignocellulosic-based filler consists essentially of or consists oflignocellulosic material, the lignocellulosic material may also includesome water or moisture content, although the lignocellulosic material,as well as the lignocellulosic-based filler, is typically dry, i.e.,does not contain any free moisture content but for that which may beassociated with the relative humidity in an environment in which thelignocellulosic-based filler is prepared, derived, formed, and/orstored. The same is typically true for other species of (a) thelignocellulosic-based filler, but is noted in regards tolignocellulosic-based fillers as lignocellulosic materials generallyinclude some water content as harvested/prepared before any drying orend use.

The lignocellulosic-based filler typically comprises carbohydratepolymers (e.g., cellulose and/or hemicellulose), and may furthercomprise an aromatic polymer (e.g., lignin). The lignocellulosic-basedfiller is typically a natural lignocellulosic material, i.e., is notsynthetically derived. For example, the lignocellulosic-based filler istypically derived from wood (hardwood, softwood, and/or plywood).Alternatively, or in addition, the lignocellulosic-based filler maycomprise lignocellulosic material from other non-wood sources, such aslignocellulosic material from plants, or other plant-derived polymers,for example agricultural by-products, chaff, sisal, bagasse, wheatstraw, kapok, ramie, henequen, corn fiber or coir, nut shells, flax,jute, hemp, kenaf, rice hulls, abaca, peanut hull, bamboo, straw,lignin, starch, or cellulose and cellulose-containing products, andcombinations thereof. The lignocellulosic-based filler may be virgin,recycled, or a combination thereof.

Alternatively, the lignocellulosic-based filler may comprise a woodfiller. “Wood” is as described in The Chemical Composition of Wood byPettersen, Roger C., U.S. Department of Agriculture, Forest Service,Forest Products Laboratory, Madison, Wis., Chapter 2. Wood may compriselignin in an amount of 18% to 35% and carbohydrate in an amount of 65%to 75%, and optionally inorganic minerals in an amount up to 10%. Thecarbohydrate portion of wood comprises cellulose and hemicellulose.Cellulose content may range from 40% to 50% of the dry wood weight andhemicellulose may range from 25% to 35%. Alpha-cellulose content may be29% to 57%, alternatively 40% to 50%, based on dry weight of the woodfiller. The wood filler is derived from wood, e.g., hardwood and/orsoftwood. Specific examples of suitable hardwoods from which the woodfiller may be derived include, but are not limited to, ash, aspen,cottonwood, basswood, birch, beech, chestnut, gum, elm eucalyptus,maple, oak, poplar, sycamore, and combinations thereof. Specificexamples of suitable softwoods from which the wood filler may be derivedinclude, but are not limited to, spruce, fir, hemlock, tamarack, larch,pine, cypress, redwood, and combinations thereof. Fillers derived fromcombinations of different hardwoods, combinations of differentsoftwoods, or combinations of hardwood(s) and softwood(s) may be usedtogether as the wood filler. Alternatively, the lignocellulosic-basedfiller may consist essentially of a wood filler. Alternatively, thelignocellulosic-based filler may consist of a wood filler.

The lignocellulosic-based filler may have any form and size, e.g., fromnanometer to millimeter particle size. For example, thelignocellulosic-based filler may comprise a powder, a pulp, a flour,sawdust, a fiber, a flake, a chip, a shaving, a strand, a scrim, awafer, a wool, a straw, a particle, or any combination thereof. Thelignocellulosic-based filler may be formed via a variety of techniquesknown to one of skill in the art, typically as a function of the formthereof. For example, the lignocellulosic-based filler can be preparedby comminuting logs, branches, industrial wood residue, or roughpulpwood. The lignocellulosic-based filler may be comminuted to adesired particle size. For example, the lignocellulosic-based filler maybe comminuted with any convenient equipment, such as a hammer mill,which results in the lignocellulosic-based filler having a particle sizesuitable for use in mixing processes. The desired particle size istypically selected by one of skill in the art based on the particularmixing process utilized and desired properties of the wood plasticcomposite article. By particle size, it is meant the dimensions of thelignocellulosic-based filler, regardless of shape, and includes, forexample, dimensions associated with the lignocellulosic-based fillerwhen in the form of fibers. As known in the art, lignocellulosic-basedfillers may be pelletized, or otherwise in the form of pellets, whichmay substantially maintain shape and dimension when incorporated intothe composition or which may form smaller particles in the composition.

The shape and dimensions of the lignocellulosic-based filler is also notspecifically restricted. For example, the lignocellulosic-based fillermay be spherical, rectangular, ovoid, irregular, and may be in the formof, for example, a powder, a flour, a fiber, a flake, a chip, a shaving,a strand, a scrim, a wafer, a wool, a straw, a particle, andcombinations thereof. Dimensions and shape are typically selected basedon the type of the lignocellulosic-based filler utilized, the selectionof other starting materials included within the WPC composition, and theend use application of the WPC article formed therewith.

Starting material (a) may be one lignocellulosic-based filler or may bea combination of two or more lignocellulosic-based polymers that differfrom one another by at least one property such as plant source fromwhich the lignocellulosic-based filler was derived, lignin content,alpha-cellulose content, method of preparation, filler shape, fillersurface area, average particle size, and/or particle size distribution.Starting material (a) may be present in the composition in an amount of15% to 70%, alternatively 40% to 70%, and alternatively 45% to 65%,based on combined weights of starting materials (a), (b), (c) and (d).

(b) Ethylene-Based Polymer

The composition described above further comprises starting material (b)an ethylene-based polymer. As used herein, “ethylene-based” polymers arepolymers prepared from ethylene monomers as the primary (i.e., greaterthan 50%) monomer component, though other co-monomers may also beemployed. “Polymer” means a macromolecular compound prepared by reacting(i.e., polymerizing) monomers of the same or different type, andincludes homopolymers and interpolymers. “Interpolymer” means a polymerprepared by the polymerization of at least two different monomer types.This generic term includes copolymers (usually employed to refer topolymers prepared from two different monomer types), and polymersprepared from more than two different monomer types (e.g., terpolymers(three different monomer types) and tetrapolymers (four differentmonomer types)).

The ethylene-based polymer can be an ethylene homopolymer. As usedherein, “homopolymer” denotes a polymer comprising repeating unitsderived from a single monomer type, but does not exclude residualamounts of other components used in preparing the homopolymer, such ascatalysts, initiators, solvents, and chain transfer agents.

Alternatively, the ethylene-based polymer can be anethylene/alpha-olefin (“α-olefin”) interpolymer having an α-olefincontent of at least 1%, alternatively at least 5%, alternatively atleast 10%, alternatively at least 15%, alternatively at least 20%, oralternatively at least 25 wt % based on the entire interpolymer weight.These interpolymers can have an α-olefin content of less than 50%,alternatively less than 45%, alternatively less than 40%, oralternatively less than 35% based on the entire interpolymer weight.When an α-olefin is employed, the α-olefin can have 3 to 20 carbon atoms(C3-C20) and be a linear, branched or cyclic α-olefin. Examples of C3-20α-olefins include propene, 1-butene, 4-methyl-1-pentene, 1-hexene,1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, and1-octadecene. The α-olefins can also have a cyclic structure such ascyclohexane or cyclopentane, resulting in an α-olefin such as3-cyclohexyl-1-propene (allyl cyclohexane) and vinyl cyclohexane.Illustrative ethylene/α-olefin interpolymers include ethylene/propylene,ethylene/1-butene, ethylene/1-hexene, ethylene/1-octene,ethylene/propylene/1-octene, ethylene/propylene/1-butene, andethylene/1-butene/1-octene.

Starting material (b) can be one ethylene-based polymer or a combinationof two or more ethylene-based polymers (e.g., a blend of two or moreethylene-based polymers that differ from one another by at least oneproperty such as monomer composition, monomer content, catalytic methodof preparation, molecular weight, molecular weight distributions, and/ordensities). If a blend of ethylene-based polymers is employed, thepolymers can be blended by any in-reactor or post-reactor process.

The ethylene-based polymer for starting material (b) may be selectedfrom the group consisting of High Density Polyethylene (HDPE), MediumDensity Polyethylene (MDPE), Low Density Polyethylene (LDPE), Linear LowDensity Polyethylene (LLDPE), Low Density Low Molecular WeightPolyethylene (LDLMWPE), and a combination thereof.

Alternatively, starting material (b) can be a LLDPE. LLDPEs aregenerally ethylene-based polymers having a heterogeneous distribution ofcomonomer (e.g., α-olefin monomer), and are characterized by short-chainbranching. For example, LLDPEs can be copolymers of ethylene andα-olefin monomers, such as those described above. LLDPEs may havedensities ranging from 0.91 g/cm³ to 0.94 g/cm³. Densities for theLLDPEs and other ethylene-based polymers described herein are determinedby ASTM D792-13. LLDPEs suitable for use herein can have a melt index(I₂) of 1 g/10 min to 20 g/10 min, alternatively >2 g/10 min,alternatively 2.3 g/10 min to 20 g/10 min, alternatively 2.3 g/10 min to12 g/10 min, alternatively 2.3 g/10 min to 6 g/10 min, alternatively 4.4g/10 min to 20 g/10 min and alternatively 6.8 g/10 min to 20 g/10 min.Values for I₂ for LLDPEs and other ethylene-based polymers aredetermined at 190° C. and 2.16 Kg according to ASTM D1238-13. The LLDPEcan have a melting temperature of at least 124° C., alternatively 124°C. to 135° C., and alternatively 124° C. to 132° C. Melting temperaturesfor LLDPEs and other polyethylene-based polymers are determined by DSCaccording to ASTM D3418-15.

LLDPE's are known in the art and may be produced by known methods. Forexample, LLDPE may be made using Ziegler-Natta catalyst systems as wellas single-site catalysts such as bis-metallocenes (sometimes referred toas “m-LLDPE”), post-metallocene catalysts, and constrained geometrycatalysts. LLDPEs include linear, substantially linear or heterogeneouspolyethylene copolymers or homopolymers. LLDPEs may contain less longchain branching than LDPEs, and LLDPEs include: substantially linearethylene polymers which are further defined in U.S. Pat. Nos. 5,272,236,5,278,272, and 5,582,923; homogeneously branched linear ethylene polymercompositions such as those in U.S. Pat. No. 3,645,992; and/orheterogeneously branched ethylene polymers such as those preparedaccording to the process disclosed in U.S. Pat. No. 4,076,698. TheLLDPEs can be made via gas-phase, solution-phase or slurrypolymerization or any combination thereof, using any type of reactor orreactor configuration known in the art.

Alternatively, the ethylene-based polymer can be a MDPE. MDPEs areethylene-based polymers having densities generally ranging from 0.926g/cm³ to 0.940 g/cm³. Alternatively, the MDPE can have a density rangingfrom 0.930 g/cm³ to 0.939 g/cm³. The MDPE can have I₂ of 0.1 g/10 min to20 g/10 min, alternatively >2 g/10 min, alternatively 2.3 g/10 min to 20g/10 min, alternatively 2.3 g/10 min to 12 g/10 min, alternatively 2.3g/10 min to 6 g/10 min, alternatively 4.4 g/10 min to 20 g/10 min andalternatively 6.8 g/10 min to 20 g/10 min. The MDPE can have a meltingtemperature of at least 124° C., alternatively 124° C. to 135° C., andalternatively 124° C. to 132° C. MDPE may be made using chromium orZiegler-Natta catalysts or using metallocene, constrained geometry, orsingle site catalysts, and typically have MWD greater than 2.5.

Alternatively, the ethylene-based polymer can be a HDPE. HDPEs areethylene-based polymers having densities of at least 0.940 g/cm³.Alternatively, the HDPE can have a density of >0.940 g/cm³ to 0.970g/cm³, alternatively >0.940 g/cm³ to 0.965 g/cm³, alternatively >0.940to 0.952 g/cm³. The HDPE can have a melting temperature of at least 124°C., alternatively 124° C. to 135° C., alternatively 124° C. to 132° C.,and alternatively 131° C. to 132° C. The HDPE can have I₂ of 0.1 g/10min to 66 g/10 min, alternatively 0.2 g/10 min to 20 g/10 min,alternatively >2 g/10 min, alternatively 2.3 g/10 min to 20 g/10 min,alternatively 3 g/10 min to 12 g/10 min, alternatively 4 g/10 min to 7g/10 min, alternatively 4.4 g/10 min to 20 g/10 min and alternatively6.8 g/10 min to 20 g/10 min. The HDPE can have a PDI of 1.0 to 30.0,alternatively 2.0 to 15.0, as determined by GPC.

The HDPE suitable for use herein can be unimodal. As used herein,“unimodal” denotes an HDPE having a MWD such that its GPC curve exhibitsonly a single peak with no discernible second peak, or even a shoulderor hump, relative to such single peak. In contrast, “bi-modal” meansthat the MWD in a GPC curve exhibits the presence of two componentpolymers, such as by having two peaks or where one component may beindicated by a hump, shoulder, or tail relative to the peak of the othercomponent polymer. The HDPE used herein may be unimodal. Unimodal HDPEis commercially available from The Dow Chemical Company of Midland,Mich., USA. HDPEs are known in the art and may be made by known methods.For example, HDPEs may be prepared with Ziegler-Natta catalysts, chromecatalysts or even metallocene catalysts.

Alternatively, the ethylene-based polymer for starting material (b) maybe selected from the group consisting of HDPE, MDPE, LLDPE, and acombination thereof. Alternatively, the ethylene-based polymer forstarting material (b) may be selected from the group consisting of HDPE,LLDPE, and a combination thereof. Alternatively, the ethylene-basedpolymer for starting material (b) may be selected from the groupconsisting of HDPE and LLDPE. Preparation methods for ethylene-basedpolymers are well known in the art. Any methods known or hereafterdiscovered for preparing an ethylene-based polymer having the desiredproperties may be employed for making the ethylene-based polymer.Suitable LLDPEs, MDPEs, and HDPEs may be prepared by methods describedabove or those disclosed in PCT Publication No. WO2018/049555 and U.S.Patent Application Publication No. 2019/0023895, and the referencescited therein. Suitable ethylene-based polymers are commerciallyavailable from The Dow Chemical Company of Midland, Mich., USA, andexamples are shown below in Table 1.

TABLE 1 Ethylene-Based Polymers Melting Density I₂ Temperature Type(g/cm³) (g/10 min) (° C.) high density polyethylene 0.950 12 132 narrowmolecular weight distribution 0.952 6.8 131 high density polyethylenehomopolymer high density polyethylene 0.952 4.4 131 high densitypolyethylene 0.952 10 130 high density polyethylene 0.954 20 130 highdensity polyethylene 0.961 0.80 133 homopolymer high densitypolyethylene 0.965 8.3 133 homopolymer with a narrow molecular weightdistribution ethylene/1-octene linear-low-density 0.917 2.3 123polyethylene copolymer ethylene/1-octene linear-low-density 0.919 6.0124 polyethylene copolymer polyethylene resin, which is a narrow 0.91725 124 molecular weight distribution copolymer

The ethylene-based polymer for use in the composition may comprisevirgin polymer and/or recycled polymer. Without wishing to be bound bytheory, it is thought that the ethylene-based polymer may comprise 50%recycled polyethylene. The recycled ethylene-based polymer, if utilized,may be sourced from industrial production streams, as well as frompost-industrial and/or post-consumer sources. The selection of thespecific ethylene-based polymer, as well as any ratio of virgin polymerto recycled polymer, if utilized in concert, is typically a function ofcost and desired properties of the WPC article formed therewith.

Starting material (b) may be present in the composition in an amount of29.5% to 84.5%, alternatively 30% to 60%, alternatively 35% to 55%, andalternatively 40% to 50%, based on combined weights of startingmaterials (a), (b), (c) and (d).

(c) Polydiorganosiloxane

The composition described above further comprises starting material (c)a polydiorganosiloxane having at least one silicon bonded alkenyl groupper molecule. The polydiorganosiloxane comprises unit formula:(R₂R′SiO_(1/2))_(a)(R₃SiO_(1/2))_(b)(R₂SiO_(2/2))_(c)(RR′SiO_(2/2))_(d),where each R is an independently selected monovalent hydrocarbon groupof 1 to 18 carbon atoms that is free of aliphatic unsaturation, each R′is an independently selected alkenyl group of 2 to 18 carbon atoms,subscript a is 0 to 2, subscript b is 0 to 2, a quantity (a+b)=2,subscript c≥0, subscript d≥0, a quantity (a+d)≥1, and a quantity(a+b+c+d) is sufficient to give the polydiorganosiloxane a viscosity of2,000 mPa·s to 60,000 mPa·s at 25° C. measured at 0.1 to 50 RPM on aBrookfield DV-III cone & plate viscometer with #CP-52 spindle. Oneskilled in the art would recognize that rotation rate decreases asviscosity increases and would be able to select the appropriate rotationrate when using this test method to measure viscosity. Alternatively,viscosity may be 2,000 mPa·s to 10,000 mPa·s, and alternatively 2,000mPa·s to 5,000 mPa·s, measured according to the test method describedabove at 5 RPM. Alternatively, subscript d may be 0 to 4, alternatively1 to 4, alternatively 1 to 3, and alternatively 2. Alternatively, aquantity (a+d) may be sufficient to provide an amount of alkenyl groups,R′, of 0.05% to 7%, alternatively 0.09% to 6.5%, based on weight of thepolydiorganosiloxane. Vinyl content may be measured by FTIR.

Alternatively, in the unit formula for the polydiorganosiloxane above,each R may be an alkyl group of 1 to 18 carbon atoms, alternatively 1 to12 carbon atoms, alternatively 1 to 6 carbon atoms, and alternatively 1to 4 carbon atoms. Suitable alkyl groups include methyl, ethyl, propyl(including n-propyl and iso-propyl), and butyl (including n-butyl,tert-butyl, sec-butyl, and iso-butyl). Alternatively, each R may bemethyl.

Alternatively, in the unit formula for the polydiorganosiloxane above,each R′ may be an alkenyl group of 2 to 12 carbon atoms, alternatively 2to 6 carbon atoms, and alternatively 2 to 4 carbon atoms. Suitablealkenyl groups include vinyl, allyl, butenyl, and hexenyl.Alternatively, each R′ may be vinyl or hexenyl. Alternatively, each R′may be vinyl.

The polydiorganosiloxane may have a terminal alkenyl group, a pendantalkenyl group, or both terminal and pendant alkenyl groups.Alternatively, in the unit formula for the polydiorganosiloxane above,subscript a may be 0 and subscript d may be greater than or equal to 1,i.e., the polydiorganosiloxane may have pendant alkenyl groups but notterminal alkenyl groups. Alternatively, subscript a may be 2, subscriptb may be 0 and subscript d may be 0, i.e., the polydiorganosiloxane maybe a bis-alkenyl-terminated polydiorganosiloxane.

The bis-alkenyl-terminated polydiorganosiloxane may comprise formula

where each R and R′ are as described above, and subscript x has a valuesufficient to give the polydiorganosiloxane the viscosity of 2,000 mPa·sto 60,000 mPa·s measured as described above. One skilled in the artwould recognize that rotation rate decreases as viscosity increases andwould be able to select the appropriate rotation rate when using thistest method to measure viscosity. Alternatively, viscosity may be 2,000mPa·s to 10,000 mPa·s, and alternatively 2,000 mPa·s to 5,000 mPa·s,measured according to the test method described above at 5 RPM.

Alternatively, each R may be an alkyl group of 1 to 18 carbon atoms,alternatively 1 to 12 carbon atoms, alternatively 1 to 6 carbon atoms,and alternatively 1 to 4 carbon atoms. Suitable alkyl groups includemethyl, ethyl, propyl (including n-propyl and iso-propyl), and butyl(including n-butyl, tert-butyl, sec-butyl, and iso-butyl).Alternatively, each R may be methyl.

Alternatively, in the formula for the polydiorganosiloxane above, eachR′ may be an alkenyl group of 2 to 12 carbon atoms, alternatively 2 to 6carbon atoms, and alternatively 2 to 4 carbon atoms. Suitable alkenylgroups include vinyl, allyl, butenyl, and hexenyl Alternatively, each R′may be vinyl or hexenyl. Alternatively, each R′ may be vinyl.

Starting material (c) may comprise a polydiorganosiloxane such as

c-1) α,ω-dimethylvinylsiloxy-terminated polydimethylsiloxane,

c-2) α,ω-dimethylvinylsiloxy-terminatedpoly(dimethylsiloxane/methylphenylsiloxane),

c-3) α,ω-dimethylvinylsiloxy-terminatedpoly(dimethylsiloxane/diphenylsiloxane),

c-4) α,ω-phenyl,methyl,vinyl-siloxy-terminated polydimethylsiloxane,

c-5) α,ω-dimethylhexenylsiloxy-terminated polydimethylsiloxane,

c-6) α,ω-dimethylhexenylsiloxy-terminatedpoly(dimethylsiloxane/methylphenylsiloxane),

c-7) α,ω-dimethylhexenylsiloxy-terminatedpoly(dimethylsiloxane/diphenylsiloxane),

c-8) α,ω-phenyl,methyl,hexenyl-siloxy-terminated polydimethylsiloxane,

c-9) α,ω-dimethylvinylsiloxy-terminatedpoly(dimethylsiloxane/methylvinylsiloxane),

c-10) α,ω-dimethylvinylsiloxy-terminated

poly(dimethylsiloxane/methylphenylsiloxane/methylvinylsiloxane),

c-11) α,ω-dimethylvinylsiloxy-terminatedpoly(dimethylsiloxane/diphenylsiloxane/methylvinylsiloxane),

c-12) α,ω-phenyl,methyl,vinyl-siloxy-terminatedpoly(dimethylsiloxane/methylvinylsiloxane),

c-13) α,ω-dimethylhexenylsiloxy-terminatedpoly(dimethylsiloxane/methylhexenylsiloxane),

c-14) α,ω-dimethylhexenylsiloxy-terminated

poly(dimethylsiloxane/methylphenylsiloxane/methylhexenylsiloxane),

c-15) α,ω-dimethylhexenylsiloxy-terminated

poly(dimethylsiloxane/diphenylsiloxane/methylhexenylsiloxane),

c-16) α,ω-phenyl, methyl, hexenyl-siloxy-terminatedpoly(dimethylsiloxane/methylhexenylsiloxane),

c-17) trimethylsiloxy-terminatedpoly(dimethylsiloxane/methylvinylsiloxane),

c-18) trimethylsiloxy-terminatedpoly(dimethylsiloxane/methylphenylsiloxane/methylvinylsiloxane),

c-19) trimethylsiloxy-terminatedpoly(dimethylsiloxane/diphenylsiloxane/methylvinylsiloxane),

c-20) trimethylsiloxy-terminated poly(dimethylsiloxane/methylhexenylsiloxane),

c-21) trimethylsiloxy-terminatedpoly(dimethylsiloxane/methylphenylsiloxane/methylhexenylsiloxane),

c-22) trimethylsiloxy-terminatedpoly(dimethylsiloxane/diphenylsiloxane/methylhexenylsiloxane),

c-23) a combination of two or more of c-1) to c-22). Alternatively, thepolydiorganosiloxane may be selected form the group consisting of c-1),c-5), c-9), c-13), c-17), c-20), and a combination of two or morethereof. Alternatively, the polydiorganosiloxane may be selected formthe group consisting of c-1), c-5), c-9), c-13), and a combination oftwo or more thereof. Alternatively, the polydiorganosiloxane may be abis-vinyldimethylsiloxy-terminated polydimethylsiloxane.Polydiorganosiloxanes described above are commercially available.Bis-vinyldimethylsiloxy-terminated polydimethylsiloxanes arecommercially available from Dow Silicones Corporation of Midland, Mich.,USA, and examples include bis-vinyldimethylsiloxy-terminatedpolydimethylsiloxane with a viscosity of 60,000 mPa·s,bis-vinyldimethylsiloxy-terminated polydimethylsiloxane with a viscosityof 10,000 mPa·s, bis-vinyldimethylsiloxy-terminated polydimethylsiloxanewith a viscosity of 5,000 mPa·s, and bis-vinyldimethylsiloxy-terminatedpolydimethylsiloxane with a viscosity of 2,000 mPa·s, where viscositywas measured 25° C. at 0.1 to 50 RPM on a Brookfield DV-III cone & plateviscometer with #CP-52 spindle. Suitable polydiorganosiloxanes may beprepared by methods known in the art such as hydrolysis and condensationof appropriate organohalosilane monomers and/or equilibration of linearand cyclic polyorganosiloxanes optionally with endcapping.

Starting material (c) may be one polydiorganosiloxane or may be acombination of two or more polydiorganosiloxanes that differ from oneanother by at least one property such as selection of R groups,selection of R′ groups, and viscosity. Starting material (c) may bepresent in the composition in an amount of 0.5% to 6%, alternatively 1%to 4%, alternatively 0.5% to 3%, alternatively 1% to 2%, andalternatively 1.5% to 2%, based on combined weights of startingmaterials (a), (b), (c) and (d).

(d) Maleated Ethylene-Based Polymer

The composition described above may further comprise starting material(d) a maleated ethylene-based polymer. As used herein, the term“maleated” indicates a polymer (e.g., an ethylene-based polymer) thathas been modified to incorporate a maleic anhydride monomer. Maleicanhydride can be incorporated into the ethylene-based polymer by anymethods known or hereafter discovered in the art. For instance, themaleic anhydride can be copolymerized with ethylene and other monomers(if present) to prepare an interpolymer having maleic anhydride residuesincorporated into the polymer backbone. Alternatively, the maleicanhydride can be graft-polymerized to the ethylene-based polymer.Techniques for copolymerizing and graft polymerizing are known in theart.

The maleated ethylene-based polymer may be an ethylene-based polymerhaving maleic anhydride grafted thereon. The ethylene-based polymerprior to being maleated can be any of the ethylene-based polymersdescribed above, alternatively, the ethylene-based polymer used formaleating may have a melt index lower than that melt index of theethylene-based polymer described above. The starting ethylene-basedpolymer can be selected from a linear-low density polyethylene, amedium-density polyethylene, and a high-density polyethylene.Alternatively, the starting ethylene-based polymer can be a high-densitypolyethylene.

The maleated ethylene-based polymer may have a density of at least 0.923g/cm³. Alternatively, the maleated ethylene-based polymer can have adensity of 0.923 g/cm³ to 0.962 g/cm³, alternatively 0.940 g/cm³ to0.962 g/cm³, and alternatively 0.923 g/cm³ to 0.940 g/cm³. Density ofthe maleated ethylene-based polymer may be determined by ASTM D792-13.The maleated ethylene-based polymer may have I₂ of 0.1 g/10 min to 25g/10 min, alternatively 0.1 g/10 min to 10 g/10 min, alternatively 1g/10 min to 2 g/10 min, alternatively 2 g/10 min to 25 g/10 min,alternatively 2 g/10 min to 12 g/10 min, alternatively 3 g/10 min to 25g/10 min, and alternatively 3 g/10 min to 12 g/10 min. Values for I₂ formaleated ethylene-based polymers are determined at 190° C. and 2.16 Kgaccording to ASTM D1238-13. The maleated ethylene-based polymer can havea maleic anhydride content of at least 0.25%, alternatively an amount of0.25% to 2.5%, and alternatively 0.5% to 1.5%, each based on the totalweight of the maleated ethylene-based polymer. Maleic anhydrideconcentrations may be determined by a titration method, which takesdried resin and titrates with 0.02N KOH to determine the amount ofmaleic anhydride. The dried polymers are titrated by dissolving 0.3 to0.5 grams of maleated ethylene-based polymer in 150 mL of refluxingxylene. Upon complete dissolution, deionized water (four drops) is addedto the solution and the solution is refluxed for 1 hour. Next, 1% thymolblue (a few drops) is added to the solution and the solution is overtitrated with 0.02N KOH in ethanol as indicated by the formation of apurple color. The solution is then back-titrated to a yellow endpointwith 0.05N HCl in isopropanol.

Suitable maleated ethylene-based polymers for starting material (d) maybe prepared by known methods, such as those disclosed in PCT PublicationNo. WO2018/049555 and the references cited therein. Alternatively,maleated ethylene-based polymers may be prepared by a process forgrafting maleic anhydride on an ethylene-based polymer, which can beinitiated by decomposing initiators to form free radicals, includingazo-containing compounds, carboxylic peroxyacids and peroxyesters, alkylhydroperoxides, and dialkyl and diacyl peroxides, among others. Many ofthese compounds and their properties have been described (Reference: J.Branderup, E. Immergut, E. Grulke, eds. “Polymer Handbook,” 4th ed.,Wiley, New York, 1999, Section II, pp. 1-76). Alternatively, the speciesthat is formed by the decomposition of the initiator may be anoxygen-based free radical. Alternatively, the initiator may be selectedfrom the group consisting of carboxylic peroxyesters, peroxyketals,dialkyl peroxides, and diacyl peroxides. Exemplary initiators, commonlyused to modify the structure of polymers, are listed in U.S. Pat. No.7,897,689, in the table spanning col. 48 line 13-col. 49 line 29.Alternatively, the grafting process for making maleated ethylene-basedpolymers can be initiated by free radicals generated by thermaloxidative processes. Suitable maleated ethylene-based polymers arecommercially available from The Dow Chemical Company, of Midland, Mich.,USA, such as those described below in Table 2.

TABLE 2 Examples of Maleated Ethylene-Based Polymers a random ethylenecopolymer incorporating high density a monomer which is polyethylenegrafted classified as being a with very high maleic maleic anhydrideanhydride copolymer Type equivalent graft level Density (g/cm³) 0.9400.962 I₂ (g/10 min) 25 2.0 Melting Temperature 108 130 (° C.)

In Table (d), densities were measured by ASTM D792-13; I₂ values weremeasured by ASTM D1238-13 at 190° C. and 2.16 Kg; and meltingtemperatures were measured by DSC according to ASTM D3418-15.

Starting material (d) can be one maleated ethylene-based polymer or acombination of two or more maleated ethylene-based polymers (e.g., ablend of two or more maleated ethylene-based polymers that differ fromone another by at least one property such as monomer composition,monomer content, catalytic method of preparation, molecular weight,molecular weight distributions, and/or densities). The maleatedethylene-based polymer may be present in the composition in an amount of0 to 4%. Alternatively, the maleated ethylene-based polymer may bepresent in an amount of 0 to 2%, alternatively >0% to 2%, alternatively1% to 3%, and alternatively 1% to 2%, based on combined weights ofstarting materials (a), (b), (c), and (d).

Additional Starting Materials

The composition described above may optionally further comprise one ormore additional starting materials. For example, one or more additionalstarting materials may be selected from the group consisting of (e) anadditional filler which is distinct from the lignocellulosic-basedfiller of starting material (a), (f) a colorant, (g) a blowing agent,(h) a UV stabilizer, (i) an antioxidant, (j) a process aid, (k) apreservative, (l) a biocide, (m) a flame retardant, (n) an impactmodifier, and (o) a combination of two or more of starting materials (e)to (n). Each additional starting material, if utilized, may be presentin the composition in an amount of greater than 0 to 30% based oncombined weights of all starting materials in the composition. Thecomposition may also include other optional additives, as known in theart. Such additives are described, for example, in Walker, Benjamin M.,and Charles P. Rader, eds. Handbook of thermoplastic elastomers. NewYork: Van Nostrand Reinhold, 1979; Murphy, John, ed. Additives forplastics handbook. Elsevier, 2001.

(e) Additional Filler

The composition may optionally further comprise starting material (e) afiller distinct from the lignocellulosic-filler described above asstarting material (a). Specific examples of suitable fillers include,but are not limited to, calcium carbonate, silica, quartz, fused quartz,talc, mica, clay, kaolin, wollastonite, feldspar, aluminum hydroxide,carbon black, and graphite. Alternatively, this filler may be a mineralfiller. Alternatively, this filler may be selected from the groupconsisting of calcium carbonate, talc, and combinations thereof.Suitable fillers are known in the art and are commercially available,e.g., ground silica is sold under the name MIN-U-SIL by U.S. Silica ofBerkeley Springs, W. Va., USA. Suitable precipitated calcium carbonatesinclude Winnofil™ SPM from Solvay and Ultra-Pflex™ and Ultra-Pflex™ 100from Specialty Minerals, Inc. of Quinnesec, Mich., USA.

The shape and dimensions of the filler is not specifically restricted.For example, the filler may be spherical, rectangular, ovoid, irregular,and may be in the form of, for example, a powder, a flour, a fiber, aflake, a chip, a shaving, a strand, a scrim, a wafer, a wool, a straw, aparticle, and combinations thereof. Dimensions and shape are typicallyselected based on the type of the filler utilized, the selection ofother starting materials included within the solid carrier component.

Regardless of the selection of the filler, the filler may be untreated,pretreated, or added in conjunction with an optional filler treatingagent, described below, which when so added may treat the filler in situor before incorporation of the filler in the composition describedabove. Alternatively, the filler may be surface treated to facilitatewetting or dispersion in the composition, which when so added may treatthe filler in situ in the composition.

The filler treating agent may comprise a silane such as an alkoxysilane,an alkoxy-functional oligosiloxane, a cyclic polyorganosiloxane, ahydroxyl-functional oligosiloxane such as a dimethyl siloxane or methylphenyl siloxane, an organosilicon compound, a stearate, or a fatty acid.The filler treating agent may comprise a single filler treating agent,or a combination of two or more filler treating agents selected fromsimilar or different types of molecules.

The filler treating agent may comprise an alkoxysilane, which may be amono-alkoxysilane, a di-alkoxysilane, a tri-alkoxysilane, or atetra-alkoxysilane. Alkoxysilane filler treating agents are exemplifiedby hexyltrimethoxysilane, octyltriethoxysilane, decyltrimethoxysilane,dodecyltrimethoxysilane, tetradecyltrimethoxysilane,phenyltrimethoxysilane, phenylethyltrimethoxysilane,octadecyltrimethoxysilane, octadecyltriethoxysilane, and a combinationthereof. In certain aspects the alkoxysilane(s) may be used incombination with silazanes, which catalyze the less reactivealkoxysilane reaction with surface hydroxyls. Such reactions aretypically performed above 100° C. with high shear with the removal ofvolatile by-products such as ammonia, methanol and water.

Suitable filler treating agents also include alkoxysilyl functionalalkylmethyl polysiloxanes, or similar materials where the hydrolyzablegroup may comprise, for example, silazane, acyloxy or oximo.

Alkoxy-functional oligosiloxanes can also be used as filler treatingagents. Alkoxy-functional oligosiloxanes and methods for theirpreparation are generally known in the art. Other filler treating agentsinclude mono-endcapped alkoxy functional polydiorganosiloxanes, i.e.,polyorganosiloxanes having alkoxy functionality at one end.

Alternatively, the filler treating agent can be any of the organosiliconcompounds typically used to treat silica fillers. Examples oforganosilicon compounds include organochlorosilanes such asmethyltrichlorosilane, dimethyldichlorosilane, and trimethylmonochlorosilane; organosiloxanes such as hydroxy-endblockeddimethylsiloxane oligomer, silicon hydride functional siloxanes,hexamethyldisiloxane, and tetramethyldivinyldisiloxane; organosilazanessuch as hexamethyldisilazane and hexamethylcyclotrisilazane; andorganoalkoxysilanes such as alkylalkoxysilanes with methyl, propyl,n-butyl, i-butyl, n-hexyl, n-octyl, i-octyl, n-decyl, dodecyl,tetradecyl, hexadecyl, or octadecyl substituents. Organoreactivealkoxysilanes can include amino, methacryloxy, vinyl, glycidoxy,epoxycyclohexyl, isocyanurato, isocyanato, mercapto, sulfido,vinyl-benzyl-amino, benzyl-amino, or phenyl-amino substituents.Alternatively, the filler treating agent may comprise anorganopolysiloxane. Alternatively, certain filler treating agents, suchas chlorosilanes, may be hydrolyzed at the filler surface.Alternatively, the filler treating agent may take advantage of multiplehydrogen bonds, either clustered or dispersed or both, as the method tobond the organosiloxane to the surface of the filler. The organosiloxanecapable of hydrogen bonding has an average, per molecule, of at leastone silicon-bonded group capable of hydrogen bonding. The group may beselected from: a monovalent organic group having multiple hydroxylfunctionalities or a monovalent organic group having at least one aminofunctional group. Hydrogen bonding may be a primary mode of bonding ofthe organosiloxane to the filler. The organosiloxane may be incapable offorming covalent bonds with the filler. The organosiloxane capable ofhydrogen bonding may be selected from the group consisting of asaccharide-siloxane polymer, an amino-functional organosiloxane, and acombination thereof. Alternatively, the polyorganosiloxane capable ofhydrogen bonding may be a saccharide-siloxane polymer.

Alternatively, the filler treating agent may comprise alkylthiols suchas octadecyl mercaptan and others, and fatty acids such as oleic acid,stearic acid, titanates, titanate coupling agents, zirconate couplingagents, and a combination thereof. One skilled in the art could optimizea filler treating agent to aid dispersion of the filler without undueexperimentation.

Starting material (e) may be one additional filler or a combination oftwo or more additional fillers that differ from one another by at leastone property such as type of filler, method of preparation, treatment orsurface chemistry, filler composition, filler shape, filler surfacearea, average particle size, and/or particle size distribution. Theadditional filler, when present, may be added to the composition in anamount of >0% to 30%, alternatively 10% to 15%, based on combinedweights of all starting materials in the composition.

When selecting starting materials to include in the composition, theremay be overlap between types of starting materials because certainstarting materials described herein may have more than one function. Forexample, (e) the additional filler may be useful as an additional fillerand as a colorant, and even as a flame retardant, e.g., carbon black.When selecting starting materials for the composition, the componentsselected are distinct from one another.

Method of Making

This invention further relates to a method for preparing a wood plasticcomposite (WPC) article. The method comprises:

(1) combining starting materials comprising

15 weight % to 70 weight % of (a) the lignocellulosic-based fillerdescribed above;

29.5 weight % to 84.5 weight % of (b) the ethylene-based polymerdescribed above;

0.5 weight % to 6 weight % of (c) the polydiorganosiloxane of unitformula(R₂R′SiO_(1/2))_(a)(R₃SiO_(1/2))_(b)(R₂SiO_(2/2))_(c)(RR′SiO_(2/2))_(d),where R and R′, and subscripts a, b, c, and d are as described above;and

0 to 4 weight % of (D) a maleated ethylene-based polymer;

each based on combined weights of starting materials (a), (b), (c), and(d); thereby preparing a composition; and

(2) preparing the WPC article from the composition.

In step (1), the composition is formed by combining at least (a) thelignocellulosic-based filler, (b) the ethylene-based polymer, and (c)the polydiorganosiloxane along with any optional starting materialspresent in the composition. When (c) the polydiorganosiloxane is in theform of a solid carrier component, the method may comprise combining (a)the lignocellulosic-based filler, (b) the ethylene-based polymer, andthe solid carrier component comprising (c) the polydiorganosiloxane.

The starting materials of the composition may be combined in any orderand via any suitable manner. For example, (b) the ethylene-based polymermay be melted before, during, and/or after formation of the composition.For example, (b) the ethylene-based polymer may be heated before and/orduring combining the starting materials such that (a) thelignocellulosic-based filler and (c) the polydiorganosiloxane arecombined with a melted form of (b) the ethylene-based polymer. Startingmaterials (a) the lignocellulosic-based filler and (c) thepolydiorganosiloxane be combined with the melted form of (b) theethylene-based polymer in any order, e.g., individually, sequentially,together, or simultaneously. Alternatively, however, (b) theethylene-based polymer may be combined with (a) thelignocellulosic-based filler and (c) the polydiorganosiloxane beforeheating or melting starting material (b) the ethylene-based polymer suchthat (b) the ethylene-base polymer is in solid and unmelted orunsoftened form when preparing the composition. Alternatively, (a) thelignocellulosic-based filler and (c) the polydiorganosiloxane may becombined and heated, then added to (b) the ethylene-based polymer insolid or liquid form when preparing the composition.

Starting material (b) the ethylene-based polymer is heated before,during, and/or after formation of the composition to a temperature thatis greater than the melting temperature of (b) the ethylene-basedpolymer, e.g., 10° C. to 90° C., alternatively 10° C. to 40° C., higherthan the melting temperature of (b) the ethylene-based polymer. Thisensures melting rather than mere softening of (b) the ethylene-basedpolymer. Alternatively, lower temperatures may be utilized incombination with shear or mixing to ensure softening and/or melting of(b) the ethylene-based polymer.

Starting material (c) the polydiorganosiloxane may be in liquid form ordelivered in the form of solid carrier component. The solid carriercomponent is a solid at room temperature and is a combination comprising(i) the polydiorganosiloxane described above as starting material (c)and (ii) a polymer component selected from the group consisting of anethylene-based polymer (as described above for starting material (b)), amaleated ethylene-based polymer (as described above for startingmaterial (d)), or a combination of both the ethylene-based polymer andthe maleated ethylene-based polymer. The solid carrier component mayoptionally further comprise a filler, as described below.

Alternatively, (a) the lignocellulosic-based filler and (c) thepolydiorganosiloxane and at least one other starting material (e.g., oneor more of the additional starting materials (e) to (n) described above)may be combined to give a mixture, and the mixture may be combined with(b) the ethylene-based polymer (and any other additional startingmaterials) to give the composition. Combining (a) thelignocellulosic-based filler and (c) the polydiorganosiloxane may bereferred to as surface treating, wetting, or pre-treating (a) thelignocellulosic-based filler, which may be further to or alternativelyto surface treating (a) the lignocellulosic-based filler as set forthherein. Alternatively, (a) the lignocellulosic-based filler and (c) thepolydiorganosiloxane may be combined by spraying, impregnation, blendingor mixing. Combining (a) the lignocellulosic-based filler and (c) thepolydiorganosiloxane may further comprise heating, e.g., to combine (c)the polydiorganosiloxane with (a) the lignocellulosic-based filler.Optionally, the resulting combination of (a) the lignocellulosic-basedfiller and (c) the polydiorganosiloxane may be compacted before beingpelletized to form the pellet if a pellet is utilized. Combining (a) thelignocellulosic-based filler and (c) the polydiorganosiloxane may beperformed in a separate process or may be integrated into an existing(e.g., extrusion) process for making a WPC article in a pre-mixing step.In the pre-mixing step, the starting materials may be blended togetherbefore feeding into an extruder, e.g., all or a portion of (a) thelignocellulosic-based filler, (c) the polydiorganosiloxane and (b) theethylene-based polymer and one or more optional starting materials, maybe mixed in the pre-mixing step and thereafter fed to an extruder.

Alternatively, (c) the polydiorganosiloxane may be present in a solidcarrier component which comprises, alternatively consists essentiallyof, alternatively consists of: (a) the lignocellulosic-based filler and(c) the polydiorganosiloxane; and the solid carrier component may beheated. Alternatively, this solid carrier component may be heated in avacuum. This can be performed for multiple reasons, such as to evaporatethe carrier vehicle (if any), to evaporate other components present inthe mixture used to form the solid carrier component or to improve themechanical properties of the solid carrier component before using in themethod.

The composition may be formed under mixing or shear, e.g., with suitablemixing equipment. For example, the composition may be formed in a vesselequipped with an agitator and/or mixing blades. The vessel may be, forexample, an internal mixer, such as a Banbury, Sigma (Z) Blade, orCavity Transfer style mixer. Alternatively or in addition, thecomposition may be formed in or processed by an extruder, which may beany extruder, e.g., a single screw extruder with rotational and/orreciprocating (co-kneader) screws, as well as multi-screw devicescomprising two or more screws, which may be aligned tangentially orpartially/fully intermeshing, revolving in either a co- orcounter-rotational direction. Alternatively, a conical extruder may beused for forming the WPC composition described herein.

In the method for preparing the WPC article as described above, themethod further comprises forming the WPC article from the composition instep 2). The composition may be prepared, e.g., in the vessel, andsubsequently removed from the vessel to form the article with separateequipment. Alternatively, the same equipment may be utilized to preparethe composition and subsequently form the WPC article. For example, thecomposition may be prepared and/or mixed in an extruder, and theextruder may be utilized to form the WPC article with the composition.Alternatively, the WPC article may be formed via molding, e.g., with aninjection, compression, or transfer molding process. The composition maybe formed independently and disposed in the mold once formed.

The method described above comprises forming the WPC article from thecomposition, which may comprise forming the composition into a desiredshape. The desired shape depends on end use applications of the WPCarticle. One of skill in the art understands how dies for extrusion andmolds for molding may be selected and created based on the desired shapeof the WPC article.

The method may be performed continuously or semi-continuously in anextruder, such as a twin screw extruder (in which the screws areconcurrently rotated, partially or fully intermeshing, alternativelycounter rotated aligned either tangentially or partially or fullyintermeshing). Starting material (c) the polydiorganosiloxane (in liquidstate or as part of a solid carrier component) may be disposed in theextruder concurrently with (a) the lignocellulosic-based filler and (b)the ethylene-based polymer. Alternatively, the polydiorganosiloxane maybe disposed in the extruder after melting (b) the ethylene-based polymerand before adding (a) the lignocellulosic-based filler. Alternatively,the polydiorganosiloxane may be disposed in the extruder after (a) thelignocellulosic-based filler and (b) the ethylene-based polymer andbefore the WPC article exits the extruder. Alternatively, (a) thelignocellulosic-based filler may be disposed in the extruderconcurrently with the polydiorganosiloxane, where they are heated toeffect surface treatment of (a) the lignocellulosic-based filler with(c) the polydiorganosiloxane, then (b) the ethylene-based polymer may bedisposed in the extruder to give a mixture and the temperature increasedto a temperature suitable for compounding the mixture and forming theWPC article. The extruder may have one or more zones, such as 1 to 3, or3 to 8, or 1 to 12, zones, where starting materials can be added. Thezones may be heated at different temperatures.

Alternatively, (b) the ethylene-based polymer may be disposed in a firstzone of the extruder, which is heated at +/−30° C. within the meltingtemperature of (b) the ethylene-based polymer. Starting material (c) thepolydiorganosiloxane, which may be delivered in a solid carriercomponent, may be disposed in a second or later zone of the extruder,which may be heated at 10° C. to 90° C. above the melting temperature of(b) the ethylene-based polymer. As noted above, the temperature utilizedis typically less than a degradation temperature of the startingmaterials of the composition. Alternatively, the die of the extruder mayalso be heated, and the temperatures utilized by the extruder, includingthe temperature of any zone and the die, may be selected such that thetemperatures do not exceed a degradation temperature of (a) thelignocellulosic-based filler. The degradation temperature of (a) thelignocellulosic-based filler is contingent on the selection thereof, asunderstood by one of skill in the art.

The method described above may be used to produce various WPC articles,such as building materials. Such WPC building materials includeresidential and/or commercial building and construction products andapplications, e.g., decking, railing, siding, fencing, window framing,trim, skirts, and flooring. When the building material is decking, themethod may optionally further comprise step 3), adding a cap stock layerafter step 2).

Solid Carrier Component Composition

As described above, (c) the polydiorganosiloxane may be added to thecomposition for preparing the WPC article in the form of a solid carriercomponent. The solid carrier component may comprise, alternatively mayconsist essentially of, alternatively may consist of:

5% to 20%, alternatively 5% to <20%, of (i) the polydiorganosiloxanedescribed above as starting material (c);

>70% to 95% of (ii) a polymer component selected from the groupconsisting of:

-   -   an ethylene-based polymer as described above for starting        material (b),    -   a maleated ethylene-based polymer as described above for        starting material (d), and    -   a combination of both the ethylene-based polymer and the        maleated ethylene-based polymer; and

0 to 10% of (iii) a filler.

Starting material (i) the polydiorganosiloxane in the solid carriercomponent is as described above for starting material (c). Startingmaterial (ii) the polymer component may comprise the ethylene-basedpolymer and may be free of maleated ethylene-based polymer. Theethylene-based polymer in the solid carrier component is as describedabove for starting material (b). Alternatively, in the solid carriercomponent the ethylene-based polymer may be selected from the groupconsisting of LLDPE, HDPE and a combination thereof, alternatively theethylene-based polymer in the solid carrier component may be HDPE.Alternatively, the ethylene-based polymer in the solid carrier componentmay be HDPE with a I₂>2 g/10 min, alternatively 2.3 g/10 min to 20 g/10min, alternatively 2.3 g/10 min to 12 g/10 min, alternatively 2.3 g/10min to 6 g/10 min, alternatively 4.4 g/10 min to 20 g/10 min, andalternatively 6.8 g/10 min to 20 g/10 min. Alternatively, (ii) thepolymer component may be a maleated ethylene-based polymer, and thesolid carrier component may be free of ethylene-based polymer. Themaleated ethylene-based polymer for use in the solid carrier componentmay be as described above for starting material (d). Alternatively, (ii)the polymer component may include both an ethylene-based polymer and amaleated ethylene-based polymer. The filler in the solid carriercomponent is optional. When present, the filler may comprise alignocellulosic-based filler as described above for starting material(a), an additional filler, such as a mineral filler, as described aboveas starting material (e), or a combination of both thelignocellulosic-based filler and the additional filler. Alternatively,the filler in the solid carrier component may be a mineral filler, andalternatively the mineral filler may be selected from the groupconsisting of talc, calcium carbonate, and a combination thereof.Alternatively, (e) the additional filler may be talc. The solid carriercomponent may alternatively comprise 5% to <20% of (i) thepolydiorganosiloxane, >70% to 95% of (ii) the polymer component, and 0to 10% of (iii) the filler. Alternatively, the solid carrier componentmay comprise 5% to 18% of (i) the polydiorganosiloxane, alternatively10% to 18%, and alternatively 10% to 15% of the polydiorganosiloxane.Alternatively, the solid carrier component may contain 0% filler.Alternatively, the solid carrier component may comprise >75% to 90% of(ii) the polymer component, alternatively 80% to 90% of (ii) the polymercomponent.

The solid carrier component is a solid at ambient temperature andpressure (e.g., 25° C. and 1 atmosphere). The solid carrier componentmay be formed by combining the starting materials in any order. Thesolid carrier component may be prepared by forming a mixed compositionfrom (ii) the polymer component and (i) the polydiorganosiloxane, andwhen present (iii), the filler, by dispersing under mixing or shear,e.g., with suitable mixing equipment. For example, the mixed compositionmay be dispersed in a vessel equipped with an agitator and/or mixingblades. The vessel may be, for example, an internal mixer, such as aBanbury, Sigma (Z) Blade, or Cavity Transfer style mixer. Alternativelyor in addition, the mixed composition may be dispersed in or processedby an extruder, which may be any extruder, e.g., a single screw extruderwith rotational and/or reciprocating (co-kneader) screws, as well asmulti-screw devices comprising two or more screws, which may be alignedtangentially or partially/fully intermeshing, revolving in either a co-or counter-rotational direction. Alternatively, a conical extruder maybe used to disperse the mixed composition described herein.

The solid carrier components prepared as described above arere-processable and may be prepared for feeding in subsequent processes.The mixed composition prepared as described above may be, for example,substantially continuous ribbons or discontinuous pellets or particlesor powders. Substantially continuous ribbons can be formed bypressurizing the mixed composition and passing it through a die tocreate continuous strands or tapes that are subsequently cooled beforebeing suitably packaged. Alternatively, the strand or tape may becomminuted to form pellets or powders. The mixing device may alsoproduce the pressure and/or heat needed to process the mixed compositionthrough the die when the mixing device is an extruder, which may be anyextruder, e.g., BUSS kneader, or a single screw extruder with rotationaland/or reciprocating (co-kneader) screws, as well as multi-screw devicescomprising two or more screws, which may be aligned tangentially orpartially/fully intermeshing, revolving in either a co- orcounter-rotational direction. A conical extruder may be used for mixingand pressurizing the mixed composition. Alternately, a gear pump may beused to generate the pressure needed for extrusion after the startingmaterials have been mixed to form the mixed. Discontinuous forms of themixed composition may be created by chopping continuous ribbons of mixedcomposition into shorter lengths. Alternatively, large pieces of mixedcomposition may be reduced to usable sizes by use of a grinder orshredder.

The solid carrier component may be formed by a method performedcontinuously or semi-continuously in an extruder, such as a twin screwextruder (in which the screws are concurrently rotated, partially orfully intermeshing, alternatively counter rotated aligned eithertangentially or partially or fully intermeshing). Alternatively, (i) thepolydiorganosiloxane may be disposed in the extruder concurrently withthe polymer component and optionally (iii) the filler. Alternatively,(i) the polydiorganosiloxane may be disposed in the extruder aftermelting (ii) the polymer component (and before adding (iii) the filler,if any will be added to the mixed composition). Alternatively, (i) thepolydiorganosiloxane may be disposed in the extruder after (iii) thefiller, when present, and before (ii) the polymer component, and beforethe mixed composition exits the extruder. Alternatively, (iii) thefiller may be disposed in the extruder concurrently with (i) thepolydiorganosiloxane, then the polymer component may be disposed in theextruder to give a mixture and the temperature increased to atemperature suitable for compounding the mixture. The extruder may haveone or more zones, such as 1 to 3, alternatively 1 to 12, alternatively3 to 12, or alternatively 3 to 10 zones, where starting materials can beadded. The zones may be heated at different temperatures and incorporatevarious functional stages including conveying, melting, mixing,deaeration, vacuum, pressurization, and forming.

Alternatively, (ii) the polymer component may be disposed in a firstzone of the extruder, which is heated at +/−30° C. within the meltingtemperature of the polymer component. The (i) polydiorganosiloxane maybe disposed in a second zone of the extruder, which is heated at 10° C.to 90° C. above the melting temperature of (ii) the polymer component.Starting material (iii), the filler, when present, is disposed in one ormore of the first, second, or subsequent zones of the extruder. As notedabove, the temperature utilized is typically less than a degradationtemperature of the starting materials of the solid carrier component.The mixture may be stripped to remove any air, moisture or byproductsprior to pressurization and forming in the die of the extruder. Thevacuum, pressurization, and forming zones may also be heated, and thetemperatures utilized by the extruder, including the temperature of anyzone and the die, does not exceed a degradation temperature of startingmaterials (i), (ii), and, when present (iii). The degradationtemperature of starting materials (i), (ii), and (iii) is contingent onthe selection thereof, as understood by one of skill in the art. Theresulting extruded strand may be comminuted by any convenient means toform the solid carrier component.

The solid carrier component is typically in particulate form, and maybe, for example, in the form of particles, pellets, or powders. Anaverage particle size of the solid carrier component is a function ofdesired properties and end use thereof. The solid carrier component maybe a powder. Alternatively, the solid carrier component may be a pellet.Pellets typically have greater average particle sizes than powders.

Examples

These examples are intended to illustrate the invention to one skilledin the art and are not to be interpreted as limiting the scope of theinvention set forth in the claims. The starting materials in Table 3were used in these examples.

TABLE 3 Starting Materials Material Description LLDPE ethylene/1-octenelinear-low-density polyethylene copolymer 1 with I₂ = 2.3 g/10 min, adensity of 0.917 g/cm³, and a melting temperature of 123° C. LLDPEethylene/1-octene linear-low-density polyethylene copolymer 2 with I₂ =25 g/10 min, a density of 0.917 g/cm³, and a melting temperature of 124°C. HDPE narrow molecular weight distribution high density poly- 1ethylene homopolymer with I₂ = 6.8 g/10 min, a density of 0.952 g/cm³,and a melting temperature of 131° C. HDPE high density polyethylenehomopolymer with I₂ = 0.8 2 g/10 min, a density of 0.961 g/cm³, and amelting temperature of 133° C. Si-60,000 bis-vinyl-terminatedpolydimethylsiloxane with a viscosity of 60,000 mPa · s Si-10,000bis-vinyl-terminated polydimethylsiloxane with a viscosity of 10,000 mPa· s Si-5,000 bis-vinyl-terminated polydimethylsiloxane with a viscosityof 5,000 mPa · s Si-2,000 bis-vinyl-terminated polydimethylsiloxane witha viscosity of 2,000 mPa · s MAPE high density polyethylene grafted withvery high maleic anhydride copolymer graft level having density of 0.962g/cm³ and I₂ = 2.0 g/10 min CaCO₃ Calcium Carbonate (untreated with aparticle size of 3 μm) Filler 40M1 Sixty mesh wood flour purchased fromAmerican Wood Fibers and composed of primarily hardwoods such as maple,poplar, ash and beech. The hydroscopic nature of wood results inmoisture contents of up to 10% despite being dried at the time ofmilling. To compensate for these variations, the wood content wasadjusted in the final composition for moisture content to result inconsistent levels of dried wood for all samples. Moisture was removedfrom the wood by use of a vacuum vent on the extruder shortly after theintroduction of the wood to the polymer component. Using this system thewater was removed for uniformly dry pellets at the time of processing.The wood flour had the following particle size distribution: >850 μm:0-1% 425-850 μm: 15-35% 250-425 μm: 30-60% 180-250 μm: 10-25% 150-180μm: 0-15% Balance Pan, <150 μm 0-23%

In Table 3, densities of ethylene-based polymers and the maleatedethylene-based polymers were measured according to ASTM D792-13, I₂values were measured according to ASTM D1238-13 at 190° C. and 2.16 Kg,and melting temperatures were measured by DSC according to ASTMD3418-15. The ethylene-based polymers and maleated ethylene-basedpolymers were commercially available from The Dow Chemical Company ofMidland, Mich., USA. Viscosities of bis-vinyl-terminatedpolydimethylsiloxanes were measured at 25° C. at 0.1 to 50 RPM on aBrookfield DV-III cone & plate viscometer with #CP-52 spindle. Thebis-vinyl-terminated polydimethylsiloxanes were commercially availablefrom Dow Silicones Corporation of Midland, Mich., USA.

Reference Example 1—Procedure for Preparing WPC Samples

For all WPC samples, (a) the lignocellulosic-based filler was addedindependent of (b) the ethylene-based polymer, and (c) thepolydiorganosiloxane through a secondary feed system located at adownstream position on the extruder barrel. By mixing of the solids intothe blend of fully melted ethylene-based polymer andpolydiorganosiloxane, higher filler content samples could be producedthan would have been possible with all materials being fed at the samelocation.

Injection molding was utilized for producing test specimens. Tensilebars were produced and tested in accordance with ASTM D638-14. Eachcomposition was processed with the same conditions for both compoundingin the twin screw extruder and injection molding equipment forconsistency. For each example, total feed rates, RPM, temperatures, andequipment configurations remained constant for each composition for boththe compounding extruders and injection molding equipment.

The parameters associated with extrusion, as well as the average breakstrength of the wood plastic composite article formed by each example,the strand quality, and color of the final injection molded tensile barsis set forth in the tables below.

Melt temperature was obtained with a thermocouple hand probe. As thismeasurement required a level of technique due to the manual method, itwas subject to a high level of variation. Experience showed that resultscould differ by up to 10° C. depending on operator and technique. In thecase of these tests, care was taken to use the same operator andtechnique.

Extruder torque was noted as a relative percent of the extruder maximumtorque.

Break strength was measured by producing five samples which wereaveraged. Testing was performed in accordance with ASTM D638-14.

Color (Y) was also measured to quantify the level of thermaldecomposition occurring in the wood filler. The Y-value or the luminancewas measure as a gauge of the darkening of the wood plastic compositeduring processing. Higher values of Y correspond to a lighter browncolor of the wood. The Y value was measured using an average of 2measurements on 5 separate injection molded tensile dog bone samples(average of 10 measurements) using a BYK spectro-guide 45/0 gloss meterwith D65 illuminant and 10° observer.

Comparative Example Compositions are shown in Table 4. Amounts of eachstarting material are in weight %.

TABLE 4 (c) Bis-vinyl- Amount of (b) Ethylene- terminated Bis-Vi- (a)Lignocellulosic- Comparative Based Polydimethylsiloxane Terminated (d)MAPE based Filler Example Polymer (PDMS) PDMS Amount Amount 1 LLDPE 1None 0 0 55 2 LLDPE 1 None 0 2 55 3 LLDPE 1 None 0 0 55 4 LLDPE 1 None 02 55 5 HDPE 2 Si-2,000 6 4 70

Table 5 shows performance of the samples prepared as shown in Table 4.

TABLE 5 Compar- Avg. ative Extruder Melt Break Exam- Torque TemperatureStrength Color ple (%) (° C.) (MPa) (Y) Observation 1 84 249 7.6 6.9 284 251 27.1 4.3 3 84 245 8.9 6.4 4 84 256 27.9 4.9 5 45 Could not ND NDHad to stop run measure due to Silicone backup in feed throat ND = NotDetermined

Working Example Compositions are shown in Table 6. Amounts of eachstarting material are in weight %.

TABLE 6 (a) Ligno- Work- (b) (c) (c) cellulosic- ing Ethylene- Bis-Vi-Bis-Vi- (d) based Exam- Based Terminated Terminated MAPE Filler plePolymer PDMS PDMS Amount Amount Amount 1 LLDPE 1 Si-10,000 1 0 55 2LLDPE 1 Si-10,000 1.5 0 55 3 LLDPE 1 Si-10,000 2 0 55 4 LLDPE 1Si-10,000 1 2 55 5 LLDPE 1 Si-10,000 1.5 2 55 6 LLDPE 1 Si-10,000 2 2 557 LLDPE 1 Si-2,000 1 0 55 8 LLDPE 1 Si-2,000 1.5 0 55 9 LLDPE 1 Si-2,0002 0 55 10 LLDPE 1 Si-2,000 1 2 55 11 LLDPE 1 Si-2,000 1.5 2 55 12 LLDPE1 Si-2,000 2 2 55 13 LLDPE 1 Si-60,000 1 0 55 14 LLDPE 1 Si-60,000 1.5 055 15 LLDPE 1 Si-60,000 2 0 55 16 LLDPE 1 Si-60,000 1 2 55 17 LLDPE 1Si-60,000 1.5 2 55 18 LLDPE 1 Si-60,000 2 2 55 19 LLDPE 1 Si-5,000 1 055 20 LLDPE 1 Si-5,000 1.5 0 55 21 LLDPE 1 Si-5,000 2 0 55 22 LLDPE 1Si-5,000 1 2 55 23 LLDPE 1 Si-5,000 1.5 2 55 24 LLDPE 1 Si-5,000 2 2 5525 HPDE 2 Si-60,000 4 1 55 26 HDPE 2 Si-2,000 4 1 55 27 HDPE 1 Si-2,0000.5 1 40 28 HDPE 1 Si-2,000 6 4 70 29 HPDE 2 Si-60,000 4 1 40

Starting Material (b) Ethylene-Based Polymer was the balance of eachsample shown in Table 6. Table 7 shows performance of the samplesprepared as shown in Table 6.

TABLE 7 Work- ing Extruder Melt Avg. Break Exam- Torque TemperatureStrength Color ple (%) (° C.) (MPa) (Y) 1 65 237 6.7 12.6 2 60 230 6.314.2 3 56 222 6.2 14.9 4 68 245 25.3 7.9 5 61 236 23.7 10.5 6 56 22722.8 12.7 7 65 240 7.0 12.1 8 58 223 6.7 15.6 9 53 222 6.5 15.8 10 61225 25.3 9.5 11 52 222 24.6 11.8 12 48 215 24.0 13.1 13 67 241 6.9 11.714 63 239 7.1 13.0 15 61 236 6.6 13.5 16 69 242 25.0 8.3 17 65 236 24.98.2 18 59 233 24.3 10.6 19 64 243 7.2 15.1 20 60 231 6.4 15.5 21 55 2276.4 16.3 22 62 235 25.2 9.6 23 55 226 23.9 11.1 24 50 220 23.0 11.8 2550 208 26.1 ND 26 45 206 30.4 ND 27 73 229 36.2 ND 28 46 192 24.4 ND 2950 216 33.7 ND ND = Not Determined

In this Reference Example A, solid carrier components in pellet formwere produced using a 26 mm twin screw extruder. Starting material (b)the ethylene-based polymer (PE), and optionally starting material (d)the maleated ethylene-based polymer (MAPE), were fed in via the feedthroat in the first barrel section. Starting material (c) thepolydiorganosiloxane (Vi-terminated PDMS) was injected into the fourthof eleven barrel sections onto a screw section with mixing. Theresulting compositions were pelletized using a Gala underwaterpelletizer for consistency and collected for testing. The resultingsamples, 31 to 40, were cooled to room temperature and aged a minimum of48 hours before any testing.

In this Reference Example B, Solid carrier components in pellet formwere produced using a 25 mm twin screw extruder. Starting material (b)the ethylene-based polymer (PE), and optionally starting material (d)the maleated ethylene-based polymer (MAPE), were fed in via the feedthroat in the first barrel section. Starting material (c) thepolydiorganosiloxane (Vi-terminated PDMS) was injected into the fourthof twelve barrel sections onto a screw section with mixing. When used,(e) the filler CaCO3 (Calcium carbonate which was untreated and had anaverage particle size of 3 μm) was also fed in via the feed throat inthe first barrel section. The resulting composition was cooled via fullimmersion water bath and pelletized using a strand pelletizer. Theresulting samples, 41 to 46, were cooled to room temperature and aged aminimum of 48 hours before any testing.

In this Reference Example C, bleed of the polydiorganosiloxane from thepellets prepared according to Reference Example A and Reference ExampleB was evaluated, as follows. Each sample (4 g) was placed intopre-weighed aluminum pans lined with Whatman™ #1 filter paper (5.5 cmdiameter) such that the surface of the aluminum pan was covered fully bythe filter paper, but the filter paper was not bent. The pellets wereevenly spread out across the filter paper in a semi-uniform layer. Thesamples were left standing at room temperature on the bench or at thesaid temperature in a convection oven for the specified amount of time.After aging, the pellets were left to stand at room temperature for atleast 4 hours, and the pellets were placed in a 20 mL scintillationvial. The filter paper was weighed to determine aged filter paperweight. Bleed was determined according to the formula below:

${{Bleed}\mspace{14mu}(\%)} = {100 \times \frac{{{Aged}\mspace{14mu}{Filter}\mspace{14mu}{Paper}\mspace{14mu}{Weight}}\; - \;{{Starting}\mspace{14mu}{Filter}\mspace{14mu}{Paper}\mspace{14mu}{Weight}}}{{Total}\mspace{14mu}{Pellet}\mspace{14mu}{Weight}\; \times \;{Fraction}\mspace{14mu}{Siloxane}\mspace{14mu}{in}\mspace{14mu}{Pellet}}}$

Compositions (Table 8), aging conditions and polydiorganosiloxane bleed(Table 9) for the pellets are reported below.

TABLE 8 Solid Carrier Components (Pellets) (a) PE (d) MAPE (c)Vi-terminated Vi-terminated PDMS (e) CaCO₃ Sample (a) PE Amt (%) (%)PDMS Amount (%) Amount (%) 31 HDPE 2 80 0 Si-10,000 20 0 32 HDPE 1 60 20Si-10,000 20 0 33 HDPE 1 65 20 Si-2,000 15 0 34 HDPE 1 65 20 Si-2,000 150 35 HDPE 1 62 20 Si-2,000 18 0 36 HDPE 1 62 20 Si-2,000 18 0 37 HDPE 160 20 Si-2,000 20 0 38 HDPE 1 60 20 Si-2,000 20 0 39 HDPE 1 58 20Si-2,000 22 0 40 HDPE 1 58 20 Si-2,000 22 0 41 none 0 95 Si-10,000 5 042 LLDPE 2 80 0 Si-2,000 20 0 43 HDPE 1 85 0 Si-2,000 15 0 44 LLDPE 1 6810 Si-10,000 22 0 45 LLDPE 2 50 30 Si-2,000 20 0 Comp 46 LLDPE 2 40 30Si-2,000 20 10

TABLE 9 Solid Carrier Components bleed and pellet properties (Pellets)Aging Aging Siloxane Could Sam- T time bleed be pel- ple (° C.) (weeks)(%) letized? Observations 31 NA NA NA No 32 70 2 21.5 Yes 33 70 2 0.8Yes 34 RT 2 0.2 Yes 35 70 2 1.2 Yes 36 RT 2 0.4 Yes 37 70 2 7.3 Yes 38RT 2 3.6 Yes 39 70 2 14.5 Yes 40 RT 2 0.8 Yes 41 70 2 0 Yes goodstrands, minimal evidence of silicone sheen in pellet water 42 70 2 0Yes good strands, no die drool 43 70 2 0 Yes even flow, potentiallyinconsistent mixing, moderate to severe die drool 44 70 2 0 Yes evenstrands, pellets have long connected tails, moderate die drool 45 70 22.0 Yes lumpy strands, sheen in water (Si), pellets feel slippery, havelong tails Comp 70 2 18.4 No surging at die, large 46 amount of siliconeat die, strand looks bad

The data in Tables 8 and 9 showed that a solid carrier component couldbe prepared with the alkenyl-functional polydiorganosiloxane describedherein and HDPE 1. However, pelletization with HDPE 2 and no MAPE wasnot possible under the conditions tested in this example; in that casebleed could not be measured as denoted by NA or “not applicable.”Furthermore, solid carrier components with low bleed (i.e., bleed of <5%of the alkenyl-functional polydiorganosiloxane) could be produced usingHDPE and maleated ethylene-based polymer (MAPE), when analkenyl-functional polydiorganosiloxane in an amount <20%, alternativelyin an amount of 15% to <20% was used.

Problem to be Solved

WPC articles are commonly produced by high shear methods such asextrusion or injection molding. Lignocellulosic-based fillers are usedto alter mechanical properties, decrease cost (because these aretypically less expensive than the ethylene-based polymers), decreasedensity, and/or meet end use requirements for various applications.Adding fillers can make the starting materials difficult to processbecause the filler generally increases the viscosity of the meltedethylene-based polymer. When the starting materials are processed with ahigh shear method, these fillers can require more work to processresulting in higher temperatures and limited extrusion rates. Thisincrease in temperature and stress can result in thermal or mechanicaldecomposition of the lignocellulosic-based filler. Similarly, someethylene-based polymers can suffer from decomposition under themechanical or thermal stress from processing. This decompositiontranslates in poor mechanical properties, discoloration, pooraesthetics, and/or other undesirable defects in the WPC articleproduced. Similarly, such processing difficulties translate in the needfor a higher energy input for processing, increased torque, and reducedprocessing speed. Combined these effects can result in lower output forcompounders and/or poor product quality.

INDUSTRIAL APPLICABILITY

By adding a polydiorganosiloxane during processing, torque can besubstantially reduced. Reducing torque also reduces energy requirementsand reduces the melt temperature of the composition. Extrusion ofcompositions that contained polydiorganosiloxane in working examples 1through 24 resulted in 48% to 69% torque as compared to comparativeexamples 1 through 4 that contained no process aid with 84% torque.Additionally, working examples 1 through 3 and 5 through 24 show reducedmelt temperature (<245° C.) as compared to comparative examples 1through 4. This temperature reduction can enable higher throughputs,improved material properties, higher filler loadings, improve propertiesof the WPC article, and/or decrease costs associated with producing theWPC article when the polydiorganosiloxane is used. This reduction intorque, pressure, work, and temperature can also minimize or eliminateprocess related decomposition of the ethylene-based polymer and/orfiller. It has been surprisingly found that this melt temperaturereduction (on the order of 5° C. to 30° C., alternatively 10° C. to 20°C.) can be obtained by using a polydiorganosiloxane with alkenylfunctional groups (e.g., bis-vinyl-terminated polydimethylsiloxane).Working examples 1 through 3, 5 through 12, 14, 15, 17, 18, and 20through 24 all showed temperatures 240° C. compared to 245° C. to 256°C. for comparative examples 1 through 4. The reduction in darkening ofthe WPC article was a measure of reduced decomposition of theethylene-based polymer and/or filler. Comparative examples 1 through 4all had lower values of luminescence (Y=4.3 to 6.9) compared to valuesfor 7.9 to 16.3 for working examples 1 through 24, demonstrating thatthe WPC articles prepared in the comparative examples were all darkerthan the WPC articles prepared by the working examples, and suggestingthat that comparative examples showed more signs of degradation than theworking examples.

It has also been found that polydiorganosiloxanes with viscosity of2,000 mPa·s to 60,000 mPa·s may provide one or more of the benefitsdescribed above to compositions for preparing WPC articles, as comparedto a comparative control composition excluding the polydiorganosiloxane.Alternatively, the viscosity of the polydiorganosiloxane may be 2,000mPa·s to 10,000 mPa·s or 2,000 mPa·s to 5,000 mPa·s.

DEFINITIONS AND USAGE OF TERMS

All amounts, ratios, and percentages herein are by weight, unlessotherwise indicated. The SUMMARY and ABSTRACT are hereby incorporated byreference. The terms “comprising” or “comprise” are used herein in theirbroadest sense to mean and encompass the notions of “including,”“include,” “consist(ing) essentially of,” and “consist(ing) of. The useof “for example,” “e.g.,” “such as,” and “including” to listillustrative examples does not limit to only the listed examples. Thus,“for example” or “such as” means “for example, but not limited to” or“such as, but not limited to” and encompasses other similar orequivalent examples. The abbreviations used herein have the definitionsin Table 10.

TABLE 10 Abbreviations Abbreviation Definition ° C. degrees Celsius cmcentimeters DSC differential scanning calorimetry FTIR Fourier TransformInfra Red g grams GPC gel permeation chromatography HDPE high-densitypolyethylene Kg kilograms LLDPE linear-low-density polyethylene MAPEmaleated ethylene-based polymer MDPE medium-density polyethylene mgmilligrams min minutes mL milliliters mm millimeters mPa · s milliPascal· seconds MWD molecular weight distribution N normal PDI polydispersityindex PE ethylene-based polymer PTFE polytetrafluoroethylene RPMrevolutions per minute μL microliters μm micrometers Vi-terminated PDMSbis-vinyl-terminated polydimethylsiloxane WPC wood plastic composite

The invention has been described in an illustrative manner, and it is tobe understood that the terminology which has been used is intended to bein the nature of words of description rather than of limitation. Withrespect to any Markush groups relied upon herein for describingparticular features or aspects, different, special, and/or unexpectedresults may be obtained from each member of the respective Markush groupindependent from all other Markush members. Each member of a Markushgroup may be relied upon individually and or in combination and providesadequate support for specific embodiments within the scope of theappended claims.

Furthermore, any ranges and subranges relied upon in describing thepresent invention independently and collectively fall within the scopeof the appended claims, and are understood to describe and contemplateall ranges including whole and/or fractional values therein, even ifsuch values are not expressly written herein. One of skill in the artreadily recognizes that the enumerated ranges and subranges sufficientlydescribe and enable various embodiments of the present invention, andsuch ranges and subranges may be further delineated into relevanthalves, thirds, quarters, fifths, and so on. As just one example, arange of “1 to 18” may be further delineated into a lower third, i.e., 1to 6, a middle third, i.e., 7 to 12, and an upper third, i.e., from 13to 18, which individually and collectively are within the scope of theappended claims, and may be relied upon individually and/or collectivelyand provide adequate support for specific embodiments within the scopeof the appended claims. In addition, with respect to the language whichdefines or modifies a range, such as “at least,” “greater than,” “lessthan,” “no more than,” and the like, it is to be understood that suchlanguage includes subranges and/or an upper or lower limit.

Embodiments of the Invention

In a first embodiment, a composition for preparing a wood plasticcomposite article comprises:

40 weight % to 69 weight % of (a) a lignocellulosic-based filler;

30 weight % to 59 weight % of (b) an ethylene-based polymer;

1 weight % to 4 weight % of (c) a bis-alkenyl-terminatedpolydialkylsiloxane of formula

where each R is an independently selected alkyl group of 1 to 18 carbonatoms, each R′ is an independently selected alkenyl group of 2 to 18carbon atoms, and subscript x has a value sufficient to give thebis-alkenyl-terminated polydialkylsiloxane a viscosity of 2,000 mPa·s to60,000 mPa·s at 25° C. measured at 0.1 to 50 RPM on a Brookfield DV-IIIcone & plate viscometer with #CP-52 spindle; and

0 to 4 weight % of (d) a maleated ethylene-based polymer;

each based on combined weights of starting materials (a), (b), (c), and(d) in said composition.

In a second embodiment, in the composition of the first embodiment,starting material (a) the lignocellulosic-based filler comprises alignocellulosic material derived from wood, plants, agriculturalby-products, chaff, sisal, bagasse, wheat straw, kapok, ramie, henequen,corn fiber or coir, nut shells, flax, jute, hemp, kenaf, rice hulls,abaca, peanut hull, bamboo, straw, lignin, starch, or cellulose andcellulose-containing products, and combinations thereof, and startingmaterial (a) is present in an amount of 45 weight % to 65 weight %.

In a third embodiment, in the composition of the first embodiment or thesecond embodiment, the lignocellulosic-based filler is a wood fillercomprising lignin in an amount of 18 weight % to 35 weight % andcarbohydrate in an amount of 65 weight % to 75 weight %, and optionallyinorganic minerals in an amount up to 10 weight %.

In a fourth embodiment, in the composition of any one of the precedingembodiments, the lignocellulosic-based filler comprises 29 weight % to57 weight % alpha-cellulose.

In a fifth embodiment, in the composition of any one of the precedingembodiments, starting material (b) comprises the ethylene-based polymer,and the ethylene-based polymer is selected from the group consisting ofHigh Density Polyethylene (HDPE), Medium Density Polyethylene (MDPE),Low Density Polyethylene (LDPE), Linear Low Density Polyethylene(LLDPE), Low Density Low Molecular Weight Polyethylene (LDLMWPE), and acombination thereof, and starting material (b) is present in an amountof 35 weight % to 50 weight %.

In a sixth embodiment, in the composition of any one of the precedingembodiments, the ethylene-based polymer is selected from the groupconsisting of HDPE, LLDPE, and a combination thereof, and theethylene-based polymer is present in an amount of 40 weight % to 45weight %.

In a seventh embodiment, in the composition of any one of the precedingembodiments, the ethylene-based polymer comprises 50% recycledpolyethylene.

In an eighth embodiment, in the composition of any one of the precedingembodiments, in starting material (c), each R is an alkyl group of 1 to12 carbon atoms, each R′ is an alkenyl group of 2 to 12 carbon atoms,subscript x has a value sufficient to give the polydiorganosiloxane aviscosity of 2,000 mPa·s to 10,000 mPa·s, and starting material (c) ispresent in an amount of 1 weight % to 2 weight %.

In a ninth embodiment, in the composition of any one of the precedingembodiments, in starting material (c) each R is an alkyl group of 1 to 6carbon atoms, each R′ is selected from the group consisting of vinyl,allyl, and hexenyl, and subscript x has a value sufficient to give thepolydiorganosiloxane a viscosity of 2,000 mPa·s to 5,000 mPa·s.

In a tenth embodiment, in the composition of any one of the precedingembodiments, starting material (c) is abis-vinyldimethylsiloxy-terminated polydimethylsiloxane.

In an eleventh embodiment, in the composition of any one of thepreceding embodiments, starting material (d) is present and startingmaterial (d) has a melt index of 2 g/10 min to 25 g/10 min measuredaccording to ASTM D1238-15 at 190° C./2.16 Kg and a maleic anhydridecontent of 0.25 weight % to 2.5 weight %.

In a twelfth embodiment, in the composition of any one of the precedingembodiments, the composition further comprises an additional startingmaterial selected from the group consisting of (e) an additional fillerwhich is distinct from the lignocellulosic-based filler of startingmaterial (a), (f) a colorant, (g) a blowing agent, (h) a UV stabilizer,(i) an antioxidant, (j) a process aid, (k) a preservative, (l) abiocide, (m) a flame retardant, (n) an impact modifier, and (o) acombination of two or more thereof.

In a thirteenth embodiment, in the composition of any one of thepreceding embodiments, starting material (e) is present in an amount of10 weight % to 15 weight %, and starting material (e) is a mineralfiller.

In a fourteenth embodiment, a method for preparing a wood plasticcomposite article comprises:

(1) preparing the composition of any one of the preceding claims bycombining the starting materials; and

(2) forming the wood plastic composite article from the composition.

In a fifteenth embodiment, the method of the fourteenth embodimentfurther comprises (i) mixing (a) the lignocellulosic based filler and(b) the ethylene-based polymer before adding (c) thebis-alkenyl-terminated polydialkylsiloxane; (ii) heating (b) theethylene-based polymer to melt (b) the ethylene-based polymer beforeand/or during forming the composition; (iii) mixing a mixture of (a) thelignocellulosic-based filler and (c) the bis-alkenyl-terminatedpolydialkylsiloxane before adding (b) the polymer or (iv) anycombination of (ii) and (i) or (iii).

In a sixteenth embodiment, the method of the fourteenth embodimentfurther comprises: (i) (c) the bis-alkenyl-terminatedpolydialkylsiloxane is a liquid when combining (c) thebis-alkenyl-terminated polydialkylsiloxane with another startingmaterial of the composition; or (ii) (c) the bis-alkenyl-terminatedpolydialkylsiloxane is present within a solid carrier component, and themethod further comprises melting the solid carrier component whencombining (c) the bis-alkenyl-terminated polydialkylsiloxane withanother starting material of the composition.

In a seventeenth embodiment, the method of any one of the fourteenth tosixteenth embodiments further comprises: (i) forming the wood plasticcomposite article from the composition further comprises forming thecomposition into a desired shape; (ii) forming the wood plasticcomposite article from the composition comprises extruding thecomposition; (iii) forming the wood plastic composite article from thecomposition comprises molding the composition; or (iv) any combinationsof (i) to (iii).

In an eighteenth embodiment, the method of any one of the fourteenth toseventeenth embodiments further comprises that the wood plasticcomposite article is useful as a building material selected from thegroup consisting of decking, railing, fencing, siding, trim, skirts, andwindow framing.

In a nineteenth embodiment, the building material of the method of theeighteenth embodiment is decking and the method further comprises: 3)adding a cap stock layer to the decking after step 2).

In a twentieth embodiment, a solid carrier component comprises:

5 weight % to <20 weight % of (i) a bis-alkenyl-terminatedpolydialkylsiloxane of formula

where each R is an independently selected alkyl group of 1 to 18 carbonatoms, each R′ is an independently selected alkenyl group of 2 to 18carbon atoms, and subscript x has a value sufficient to give thepolydiorganosiloxane a viscosity of 2,000 mPa·s to 60,000 mPa·s at 25°C. measured at 0.1 to 50 RPM on a Brookfield DV-III cone & plateviscometer with #CP-52 spindle; and

>70 weight % to 95 weight % of (ii) a polymer component selected fromthe group consisting of:

an ethylene-based polymer having a melt index >2 g/10 min measuredaccording to ASTM D1238-13 at 190° C. and 2.16 Kg,

a maleated ethylene-based polymer, and

a combination of both (b) and (d); and

0 to 10% of (iii) a filler.

In a twenty-first embodiment, the bis-alkenyl-terminatedpolydialkylsiloxane in the solid carrier component of the twentiethembodiment has each R is an alkyl group of 1 to 12 carbon atoms, each R′is an alkenyl group of 2 to 12 carbon atoms, subscript x has a valuesufficient to give the polydiorganosiloxane a viscosity of 2,000 mPa·sto 10,000 mPa·s, and the polydiorganosiloxane is present in an amount of10 weight % to 20 weight % based on combined weights of all startingmaterials in the solid carrier component.

In a twenty-second embodiment, the polydiorganosiloxane in the solidcarrier component of the twentieth embodiment or the twenty-firstembodiment has each R is an alkyl group of 1 to 6 carbon atoms, each R′is independently selected from the group consisting of vinyl, allyl, andhexenyl, and subscript x has a value sufficient to give thepolydiorganosiloxane a viscosity of 2,000 mPa·s to 5,000 mPa·s.

In a twenty-third embodiment, the polydiorganosiloxane in the solidcarrier component of any one of the twentieth to twenty-secondembodiments is a bis-vinyl-terminated polydimethylsiloxane.

In a twenty-fourth embodiment, the polymer component in the solidcarrier component of any one of the twentieth to twenty-thirdembodiments comprises the ethylene-based polymer.

In a twenty-fifth embodiment, the polymer component in the solid carriercomponent of any one of the twentieth to twenty-fourth embodimentscomprises high density polyethylene.

In a twenty-sixth embodiment, the polymer component in the solid carriercomponent in any one of the twentieth to twenty-fifth embodimentscomprises high density polyethylene with a melt index of 2.3 g/10 min to20 g/10 min.

In a twenty-seventh embodiment, the polymer component in any one of thetwentieth to twenty-sixth embodiments further comprises the maleatedethylene-based polymer.

In a twenty-eighth embodiment, the polymer component in any one of thetwentieth to twenty-fifth embodiments is free of the maleatedethylene-based polymer.

In a twenty-ninth embodiment, the polymer component in any one of thetwentieth to twenty-third embodiments comprises the maleatedethylene-based polymer and is free of the ethylene-based polymer.

In a thirtieth embodiment, the filler is present in the solid carriercomponent in any one of the twentieth to twenty-ninth embodiments, andthe filler comprises talc.

In a thirty-first embodiment, the solid carrier component in any one ofthe twentieth to twenty-ninth embodiments is free of filler.

The invention claimed is:
 1. A composition for preparing a wood plasticcomposite article, said composition comprising: 15 weight % to 70 weight% of (a) a lignocellulosic-based filler; 29.5 weight % to 84.5 weight %of (b) an ethylene-based polymer; 0.5 weight % to 6 weight % of (c) apolydiorganosiloxane of unit formula:(R₂R′SiO_(1/2))_(a)(R₃SiO_(1/2))_(b)(R₂SiO_(2/2))_(c)(RR′SiO_(2/2))_(d),where each R is an independently selected monovalent hydrocarbon groupof 1 to 18 carbon atoms that is free of aliphatic unsaturation, each R′is an independently selected alkenyl group of 2 to 18 carbon atoms,subscript a is 0 to 2, subscript b is 0 to 2, a quantity (a+b)=2,subscript c≥0, subscript d≥0, a quantity (a+d)≥1, and a quantity(a+b+c+d) is sufficient to give the polydiorganosiloxane a viscosity of2,000 mPa·s to 60,000 mPa·s at 25° C. measured at 0.1 to 50 RPM on aBrookfield DV-III cone & plate viscometer with #CP-52 spindle; and 0 to4 weight % of (d) a maleated ethylene-based polymer; each based oncombined weights of starting materials (a), (b), (c), and (d) in saidcomposition.
 2. The composition of claim 1, where starting material (a)the lignocellulosic-based filler comprises a lignocellulosic materialderived from wood, plants, agricultural by-products, chaff, sisal,bagasse, wheat straw, kapok, ramie, henequen, corn fiber or coir, nutshells, flax, jute, hemp, kenaf, rice hulls, abaca, peanut hull, bamboo,straw, lignin, starch, or cellulose and cellulose-containing products,and combinations thereof, and starting material (a) is present in anamount of 45 weight % to 65 weight %.
 3. The composition of claim 1,where starting material (b) the ethylene-based polymer is selected fromthe group consisting of High Density Polyethylene (HDPE), Medium DensityPolyethylene (MDPE), Low Density Polyethylene (LDPE), Linear Low DensityPolyethylene (LLDPE), Low Density Low Molecular Weight Polyethylene(LDLMWPE), and a combination thereof, and starting material (b) ispresent in an amount of 30 weight % to 65 weight %.
 4. The compositionof claim 3, where the ethylene-based polymer comprises LLDPE.
 5. Thecomposition of claim 3, where the ethylene-based polymer comprises 50%recycled polyethylene.
 6. The composition of claim 1, where thepolydiorganosiloxane is a bis-alkenyl-terminated polydiorganosiloxane offormula

where each R is an independently selected monovalent hydrocarbon groupof 1 to 18 carbon atoms that is free of aliphatic unsaturation, each R′is an independently selected alkenyl group of 2 to 18 carbon atoms, andsubscript x has a value sufficient to give the polydiorganosiloxane aviscosity of 2,000 mPa·s to 60,000 mPa·s measured at 25° C. at 0.1 to 50RPM on a Brookfield DV-III cone & plate viscometer with #CP-52 spindle.7. The composition of claim 6, where each R is an alkyl group of 1 to 12carbon atoms, each R′ is an alkenyl group of 2 to 12 carbon atoms, andsubscript x has a value sufficient to give the polydiorganosiloxane aviscosity of 2,000 mPa·s to 10,000 mPa·s, and the polydiorganosiloxaneis present in an amount of 1.5 weight % to 2 weight %.
 8. Thecomposition of claim 7, where in each R is a methyl group, each R′ is avinyl group, subscript x has a value sufficient to give thepolydiorganosiloxane a viscosity of 2,000 mPa·s to 5,000 mPa·s.
 9. Thecomposition of claim 1, where the maleated ethylene-based polymer ispresent and the maleated ethylene-based polymer has a melt index of 0.1g/10 min to 25 g/10 min measured according to ASTM D1238-13 at 190° C.and 2.16 Kg and a maleic anhydride content of 0.25 weight % to 2.5weight %.
 10. The composition of claim 1, further comprising anadditional starting material selected from the group consisting of (e)an additional filler which is distinct from the lignocellulosic-basedfiller of starting material (a), (f) a colorant, (g) a blowing agent,(h) a UV stabilizer, (i) an antioxidant, (j) a process aid, (k) apreservative, (l) a biocide, (m) a flame retardant, (n) an impactmodifier, and (o) a combination of two or more thereof.
 11. A method forpreparing a wood plastic composite article, said method comprising: (1)combining starting materials comprising 15 weight % to 70 weight % of(a) a lignocellulosic-based filler; 29.5 weight % to 84.5 weight % of(b) an ethylene-based polymer; 0.5 weight % to 6 weight % of (c) apolydiorganosiloxane comprising unit formula:(R₂R′SiO_(1/2))_(a)(R₃SiO_(1/2))_(b)(R₂SiO_(2/2))_(c)(RR′SiO_(2/2))_(d),where each R is an independently selected monovalent hydrocarbon groupof 1 to 18 carbon atoms that is free of aliphatic unsaturation, each R′is an independently selected alkenyl group of 2 to 18 carbon atoms,subscript a is 0 to 2, subscript b is 0 to 2, a quantity (a+b)=2,subscript c≥0, subscript d≥0, a quantity (a+d)≥1, and a quantity(a+b+c+d) is sufficient to give the polydiorganosiloxane a viscosity of2,000 mPa·s to 60,000 mPa·s at 25° C. measured at 0.1 to 50 RPM on aBrookfield DV-III cone & plate viscometer with #CP-52 spindle; eachbased on combined weights of starting materials (a), (b), (c), and (d);thereby preparing a composition; and (2) preparing the wood plasticcomposite article from the composition.
 12. The method of claim 11,where the method further comprises (i) mixing (a) the lignocellulosicbased filler and (b) the polymer before adding (c) thepolydiorganosiloxane; (ii) heating (b) the polymer to melt (b) thepolymer prior to and/or during forming the composition; (iii) mixing amixture of (a) the lignocellulosic-based filler and (c) thepolydiorganosiloxane before adding (b) the polymer or (iv) anycombination of (ii) and (i) or (iii).
 13. The method of claim 11, where:(i) (c) the polydiorganosiloxane is a liquid when combining (c) thepolydiorganosiloxane with another starting material of the composition;or (ii) (c) the polydiorganosiloxane is present within a solid carriercomponent, and the method further comprises melting the solid carriercomponent when combining (c) the polydiorganosiloxane with anotherstarting material of the composition.
 14. The method of claim 11,wherein: (i) preparing the wood plastic composite article from thecomposition further comprises forming the composition into a desiredshape; (ii) preparing the wood plastic composite article from thecomposition comprises extruding the composition; (iii) preparing thewood plastic composite article from the composition comprises moldingthe composition; or (iv) any combinations of (i) to (iii).
 15. Thecomposition of claim 1, where (c) the polydiorganosiloxane has aviscosity of 2,000 mPa·s to 5,000 mPa·s.